Method for beamforming transmissions from a network element having a plurality of antennas, and the network element

1. A method of beamforming transmissions from a network element having a plurality of antennas, comprising:

receiving a pilot signal from a terminal at a target antenna of the plurality of antennas of the network element;

determining an uplink channel estimate for the target antenna based on the received pilot signal;

obtaining a calibration coefficient associated with the target antenna, the calibration coefficient based on a channel estimate between the target antenna and a different one of the plurality of antennas; and

beamforming a transmission to the terminal using at least the target antenna based on the determined uplink channel estimate and the obtained calibration coefficient.

2. The method of claim 1 , wherein the obtaining obtains the calibration coefficient from a memory.

3. The method of claim 2 , further comprising:

determining a first channel estimate for a channel from the target antenna to the different one of the plurality of antennas;

determining a second channel estimate for a channel from the different one of the plurality of antennas to the target antenna;

determining the calibration coefficient based on the first and second coefficients; and

storing the calibration coefficient in the memory.

4. The method of claim 2 , further comprising:

determining first transmission and reception frequency responses associated with the target antenna;

determining second transmission and reception frequency responses associated with the different one of the plurality of antennas;

determining the calibration coefficient based on the first transmission and reception frequency responses and the second transmission and reception frequency responses; and

storing the calibration coefficient in the memory.

5. The method of claim 2 , wherein the obtaining includes determining a channel estimate between the target antenna and the different one of the plurality of antennas.

6. The method of claim 2 , wherein the obtaining includes determining a transmission and reception frequency responses associated with the target antenna.

7. The method of claim 1 , further comprising:

determining first transmission and reception frequency responses associated with the target antenna;

determining second transmission and reception frequency responses associated with the different one of the plurality of antennas;

determining the calibration coefficient based on the first transmission and reception frequency responses and the second transmission and reception frequency responses; and

the obtaining obtains the determined calibration coefficient.

8. The method of claim 1 , further comprising:

determining first transmission and reception frequency responses associated with the target antenna;

determining second transmission and reception frequency responses associated with the different one of the plurality of antennas;

determining the calibration coefficient based on the first transmission and reception frequency responses and the second transmission and reception frequency responses; and

the obtaining obtains the determined calibration coefficient.

9. The method of claim 1 , wherein the beamforming is conjugate beamforming.

10. The method of claim 1 , wherein the beamforming is zero forcing beamforming.

11. The method of claim 1 , beamform wherein the beamforming increase received signal strength at the terminal coherently.

12. The method of claim 1 , wherein the beamforming includes removing phase error in beamforming the transmission.

13. The method of claim 12 , wherein the beamforming determines a calibration constant based on a frequency response of transmission and reception sides associated with the target antenna, and the beamforming removes the phase error based on the calibration coefficient.

14. A method of beamforming transmissions from a network element having a plurality of antennas, comprising:

receiving a pilot signal from a terminal at a plurality of antennas;

determining an uplink channel estimate associated with each of the plurality of antennas based on the pilot signal received at the plurality of antennas;

beamforming transmissions from the plurality of antennas to the terminal based on the determined uplink channel estimate and a plurality of calibration coefficients, each calibration coefficient based on a channel estimate between a pair of the plurality of antennas.

15. A base station, comprising:

a plurality of antennas;

a memory configured to store at least one calibration coefficient associated with a target one of the plurality of antennas, the calibration coefficient based on a channel estimate between the target antenna and a different one of the plurality of antennas;

a processor configured to determine an uplink channel estimate for the target antenna based on a pilot signal received at the target antenna from a terminal, and configured to beamform a transmission to the terminal using at least the target antenna based on the determined uplink channel estimate and the stored calibration coefficient.